Rename the file micronaut-amazon-awssdk-lambda-annotation-processor-2.1.7-micronaut-3.0-javadoc.jar to micronaut-amazon-awssdk-lambda-annotation-processor-2.1.7-micronaut-3.0-javadoc.zip
Use your favourite unzip tool (WinRAR / WinZIP) to extract it, now you have a folder micronaut-amazon-awssdk-lambda-annotation-processor-2.1.7-micronaut-3.0-javadoc
Double click index.html will open the index page on your default web browser.